Project Summary This project is designed to research and develop means for the early detection of impending roof falls in underground mines and means for alerting maintenance crews to take proactive action to prevent disaster, thereby saving lives and preventing injuries to miners. This will be achieved by detecting structural changes in the roof infrastructure and providing an alarm signal when a critical level of damage, that requires maintenance attention, has occurred. For the long-range program, the objective is to provide a system that produces an audible alarm in the maintenance office as soon as the damage to the structure has occurred, and displays on a video screen the location where the problem exists in a pattern that specifies the degree of infrastructure weakening that took place. The purpose of phase II is to produce an MSHA approved prototype ready for reduction to a product suitable for mass production and commercialization.